CN104037277A - LED flip chip manufacturing method and LED flip chip - Google Patents

Abstract

The invention provides a method for preparing a flip-chip LED chip and a flip-chip LED chip. The method provided by the present invention includes: sequentially growing a buffer layer, an intrinsic semiconductor layer, an N-type semiconductor layer, a light-emitting layer, and a P-type semiconductor layer on a substrate to form an epitaxial layer; removing part of the P-type semiconductor layer and part of the light-emitting layer , exposing part of the N-type semiconductor layer; on the surface of the P-type semiconductor layer, a transparent conductive layer and a DBR layer are sequentially formed; on the surface of the DBR layer, a metal reflection layer is formed, and a through hole is formed at the same position of the DBR layer and the metal reflection layer, so as to Part of the N-type semiconductor layer and part of the transparent conductive layer are exposed; and a metal conductive layer is formed on the through hole of the DBR layer and the metal reflective layer. The method provided by the present invention solves the problem that the flip-chip LED chips prepared in the prior art cannot meet the requirements of reflectivity and conductivity when preparing the metal reflective layer due to the performance limitation of the metal material, which leads to the problem of reduced reflection efficiency.

Description

Preparation method of flip-chip LED chip and flip-chip LED chip

technical field

The invention relates to chip manufacturing technology, in particular to a method for preparing a flip-chip LED chip and the flip-chip LED chip.

Background technique

With the development of light-emitting diode (Light Emitting Diode, referred to as: LED) technology, LED chips have been widely used in lighting, indication, display and backlight, because the flip-chip LED chip can avoid the light shielding of metal electrodes, through As a light-transmitting surface, the substrate increases the area of the light-emitting area, and can take into account the advantages of the balance of light transmittance and square resistance, and has gradually replaced the traditional front-mounted LED chips.

The current flip-chip LED chip usually forms a reflective layer on the epitaxial surface, which can reflect the light of the epitaxial layer to the substrate and emit it. The material of the reflective layer can be a metal with high reflectivity such as silver (Ag), aluminum (Al) etc., or a non-metallic reflective layer formed by a distributed Bragg reflector (Distributed Bragg Reflection, referred to as: DBR), or a combination of DBR and metal materials; Make full use of the insulating properties of DBR and the conductive properties of metals for chip design; usually, the metal reflective layer can form ohmic contacts with the transparent conductive layer and the epitaxial layer respectively, so the choice of metal materials is greatly limited , specifically, the metal reflective layer not only needs to have high reflectivity, but also needs to form a good ohmic contact, that is, needs high conductivity. For example, chromium (Cr), titanium (Ti) or nickel ( Ni), and reflective layers formed by metals such as aluminum (Al) or silver (Ag), in which Cr, Ti or Ni are used for electrical contact and adhesion, and Al or Ag is used for reflecting light, but the addition of Cr, Ti or Ni greatly The reflective effect of the metal reflective layer is reduced.

Due to the performance limitations of metal materials, the flip-chip LED chips prepared in the prior art cannot meet the requirements of reflectivity and conductivity when preparing the metal reflective layer, and usually need to sacrifice part of the reflectivity to reduce the reflection efficiency.

Contents of the invention

The invention provides a method for preparing a flip-chip LED chip and a flip-chip LED chip to solve the problem that the flip-chip LED chips prepared in the prior art cannot balance reflectivity and conductivity due to the performance limitation of metal materials when preparing a metal reflective layer. The requirements lead to the problem of reduced reflection efficiency.

The invention provides a method for preparing a flip-chip LED chip, comprising:

growing a buffer layer, an intrinsic semiconductor layer, an N-type semiconductor layer, a light-emitting layer, and a P-type semiconductor layer sequentially on the substrate to form an epitaxial layer;

removing part of the P-type semiconductor layer and part of the light-emitting layer to expose part of the N-type semiconductor layer;

A transparent conductive layer and a distributed Bragg reflector DBR layer are sequentially formed on the surface of the P-type semiconductor layer, wherein the transparent conductive layer covers the P-type semiconductor layer, and the DBR layer covers the transparent conductive layer and the DBR layer. The N-type semiconductor layer, the light-emitting layer and the P-type semiconductor layer;

Forming a metal reflective layer on the surface of the DBR layer, and forming a through hole at the same position of the DBR layer and the metal reflective layer to expose part of the N-type semiconductor layer and part of the transparent conductive layer;

A metal conductive layer is formed on the through holes of the DBR layer and the metal reflective layer.

The method as shown above, wherein, forming a metal reflective layer on the surface of the DBR layer, and forming a through hole at the same position of the DBR layer and the metal reflective layer includes:

directly forming the metal reflective layer on the surface of the DBR layer;

Via holes passing through the metal reflective layer and through the DBR layer are simultaneously formed on the DBR layer and the metal reflective layer.

The method as shown above, wherein, forming a metal reflective layer on the surface of the DBR layer, and forming a through hole at the same position of the DBR layer and the metal reflective layer includes:

forming vias on the DBR layer;

Form a metal reflective layer on the surface of the DBR layer, and form a through hole on the metal reflective layer at the position of the through hole of the DBR layer, wherein the coverage of the metal reflective layer does not exceed the DBR layer coverage.

The method as shown above, wherein the forming the through hole on the metal reflective layer at the position of the through hole of the DBR layer includes:

A through hole is formed on the metal reflective layer, the through hole includes a through hole for forming the metal conductive layer at the same position as the through hole of the DBR layer, and is used for isolating the metal reflective layer into isolation holes of the first metal reflective layer and the second metal reflective layer which are independent of each other;

Wherein, the through hole on the first metal reflective layer is located on the N-type semiconductor layer and exposes part of the N-type semiconductor layer, and the through hole on the second metal reflective layer is located on the transparent conductive layer. and expose part of the transparent conductive layer.

The method as above, wherein the metal reflective layer is formed of a single material; or,

The metal reflective layer is composed of a reflective layer, a transition layer and a barrier layer formed sequentially by multiple materials.

The method as shown above, wherein the forming a metal conductive layer on the through hole of the DBR layer and the metal reflective layer includes:

A metal conductive layer filling the through holes of the DBR layer and the through holes of the metal reflective layer is formed on the through holes of the DBR layer and the metal reflective layer, and the metal conductive layer is formed on the through holes of the through holes. Locations form mutually independent regions.

The method as shown above, wherein, the metal conductive layer includes a first metal conductive layer and a second metal conductive layer, the first metal conductive layer is located on the first metal reflective layer, and the second metal conductive layer is located on the second metal conductive layer On the second metal reflective layer; then the metal conductive layer is formed on the through hole of the DBR layer and the metal reflective layer, including:

removing part of the metal reflective layer, so that the through holes on the first metal reflective layer and the through holes on the second metal reflective layer communicate with each other;

On the through holes of the DBR layer and the metal reflective layer, respectively connect the first metal conductive layer and the second metal conductive layer, wherein the first metal conductive layer is electrically conductive with the second metal Layers are independent of each other.

The above method, further comprising: forming an insulating layer on the metal reflective layer and the metal conductive layer, and forming a through hole exposing part of the metal conductive layer on the insulating layer;

A metal electrode layer is formed on the through hole of the insulating layer.

The above method, wherein the insulating layer includes at least two through holes, wherein one through hole is located on the first conductive metal layer, and the other through hole is located on the second conductive metal layer, respectively arranged at both ends of the flip-chip LED chip;

The metal electrode layer includes a first metal electrode layer covering the first metal conducting layer and a second metal electrode layer covering the second metal conducting layer.

The present invention provides another flip-chip LED chip, which is prepared by using the preparation method of the flip-chip LED chip provided by the present invention.

The method for preparing a flip-chip LED chip provided in this embodiment and the flip-chip LED chip are formed by forming an epitaxial layer consisting of a buffer layer, an intrinsic semiconductor layer, an N-type semiconductor layer, a light-emitting layer, and a P-type semiconductor layer on a substrate. After removing part of the P-type semiconductor layer and part of the light-emitting layer and exposing part of the N-type semiconductor layer, a transparent conductive layer, a DBR layer, and a metal reflective layer are sequentially formed on the surface of the P-type semiconductor layer, and the DBR layer and the metal reflective layer A through hole is formed at the same position of the layer to expose part of the N-type semiconductor layer and part of the transparent conductive layer, and then a metal conductive layer is formed on the through hole. In this embodiment, a metal reflective layer for reflecting light and a metal reflective layer for The flip-chip LED chip prepared by the metal conductive layer in ohmic contact solves the problem of the flip-chip LED chip prepared by the prior art. Due to the performance limitation of the metal material, the requirements of reflectivity and conductivity cannot be taken into account when preparing the metal reflective layer. The problem of reduced reflection efficiency improves the luminous efficiency of flip-chip LED chips.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is a flowchart of an embodiment of a method for preparing a flip-chip LED chip provided by the present invention;

FIG. 2 is a schematic diagram of the chip structure of the process of a manufacturing method of a flip-chip LED chip provided by the embodiment shown in FIG. 1;

Fig. 3 is a chip structure schematic diagram of the process of a manufacturing method of a flip-chip LED chip provided by the embodiment shown in Fig. 1;

FIG. 4 is a schematic diagram of the chip structure of the process of a manufacturing method of a flip-chip LED chip provided by the embodiment shown in FIG. 1;

FIG. 5 is a schematic diagram of the chip structure of the process of a manufacturing method of a flip-chip LED chip provided by the embodiment shown in FIG. 1;

FIG. 6 is a schematic diagram of the chip structure of the process of a manufacturing method of a flip-chip LED chip provided by the embodiment shown in FIG. 1;

Fig. 7 is a top view of a metal conductive layer of a flip-chip LED chip provided by the embodiment shown in Fig. 1;

Fig. 8 is a flowchart of another embodiment of a method for preparing a flip-chip LED chip provided by the present invention;

Fig. 9 is a top view of a metal conductive layer of a flip-chip LED chip provided by the embodiment shown in Fig. 8;

FIG. 10 is a schematic diagram of the chip structure in the process of a manufacturing method of a flip-chip LED chip provided by the embodiment shown in FIG. 8 .

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

FIG. 1 is a flowchart of an embodiment of a method for manufacturing a flip-chip LED chip provided by the present invention. As shown in Figure 1, the method of this embodiment may include:

S110, sequentially growing a buffer layer, an intrinsic semiconductor layer, an N-type semiconductor layer, a light-emitting layer, and a P-type semiconductor layer on the substrate to form an epitaxial layer.

In the process of chip preparation, semiconductor wafers are usually used as the substrate material. When preparing flip-chip LED chips in this embodiment, the sapphire commonly used as the substrate material is used as an example to illustrate, as shown in Figure 2. 1 is a schematic diagram of the chip structure of the manufacturing process of a flip-chip LED chip provided by the embodiment. On the substrate 100, a buffer layer 110, an intrinsic semiconductor layer (not shown in the figure), and an N-type semiconductor layer are sequentially grown on the substrate 100. Semiconductor layer 120, light-emitting layer (not shown) and P-type semiconductor layer 130; present embodiment provides in the prepared flip-chip LED chip, N-type semiconductor layer 120 can be N-type gallium nitride layer for example, P-type The semiconductor layer 130 may be, for example, a P-type gallium nitride layer.

It should be noted that both the intrinsic semiconductor layer and the light-emitting layer in the embodiments of the present invention are conventional process layers in the fabrication process of flip-chip LED chips. Therefore, in the chip structure schematic diagrams of the process provided in the following embodiments of the present invention Neither is shown.

S120, removing part of the P-type semiconductor layer and part of the light emitting layer to expose part of the N-type semiconductor layer.

The preparation of the flip-chip LED chip is to form a PN junction, and a metal electrode layer is respectively made on the P-type region and the N-type region, that is, the N-type semiconductor layer 120 and the P-type semiconductor layer 130 in this embodiment. Therefore, in In this embodiment, a photoresist mask pattern is made by a photolithography process, and then an Inductively Coupled Plasma (Inductively Coupled Plasma, referred to as: ICP) etching equipment is used for the process window pattern preset on the mask pattern. The P-type semiconductor layer 130 and the light-emitting layer are selectively etched to expose part of the N-type semiconductor layer 120, that is, the N-type semiconductor layer 120 at the preset process window pattern position on the mask pattern, as shown in FIG. 1 is a schematic diagram of the chip structure of the manufacturing process of a flip-chip LED chip provided by the embodiment.

S130, sequentially forming a transparent conductive layer and a DBR layer on the surface of the P-type semiconductor layer, wherein the transparent conductive layer covers the P-type semiconductor layer, and the DBR layer covers the transparent conductive layer, the N-type semiconductor layer, the light-emitting layer and The P-type semiconductor layer.

In this embodiment, the transparent conductive layer 140 grown on the basis of the above-mentioned structure shown in FIG. 3 can be formed by evaporation or sputtering. Abbreviation: ITO), indium oxide (InO), tin oxide (SnO), arsenic trioxide (As ₂ O ₃ , abbreviation: ATO), zinc oxide (ZnO), gallium phosphide (GaP) or a combination thereof, and through light The photoresist mask pattern is produced by the etching process, and then the preset process window pattern is formed by the etching process. The transparent conductive layer 140 covers the top of the P-type semiconductor layer 130, that is, the etched process window is the exposed N-type semiconductor layer. 120 area; similarly, the DBR reflective layer 150 is grown by evaporation or sputtering, and the material of the DBR reflective layer 150 is usually an oxide, such as silicon oxide (SiO ₂ ) or titanium oxide (Ti ₃ O ₅ ); Specifically, the DBR layer 150 covers the transparent conductive layer 140, the N-type semiconductor layer 120, the light-emitting layer and the P-type semiconductor layer 130, since the P-type semiconductor layer 130, part of light-emitting layer and part of the N-type semiconductor layer 120, therefore, the DBR reflective layer 150 can completely cover the sidewalls formed by the N-type semiconductor layer 120 and the light-emitting layer P-type semiconductor layer 130; as shown in Figure 4, it is 1 is a schematic diagram of the chip structure of the manufacturing process of a flip-chip LED chip provided by the embodiment.

It should be noted that in this embodiment, the preset process window patterns on the mask patterns in different process steps are usually different, and are determined according to the structure of the flip-chip LED chip to be prepared, and have been pre-set before the process production. This mask pattern is prepared.

S140, forming a metal reflective layer on the surface of the DBR layer, and forming via holes at the same positions of the DBR layer and the metal reflective layer, so as to expose part of the N-type semiconductor layer and part of the transparent conductive layer.

In this embodiment, similarly, a photoresist mask pattern is made by a photolithography process, and then the process window pattern preset on the mask pattern is removed by plasma etching, chemical etching or stripping, to expose a partially transparent The conductive layer 140 and part of the N-type semiconductor layer 120; it should be noted that the exposed transparent conductive layer 140 is located above the P-type semiconductor layer 130 for forming the ohmic contact layer of the P-type region, and the exposed N-type semiconductor layer 120 is used to form the ohmic contact layer of the N-type region, as shown in FIG. 5 , which is a schematic diagram of the chip structure in the process of a manufacturing method of a flip-chip LED chip provided by the embodiment shown in FIG. 1 .

In the flip-chip LED chip prepared by the method of this embodiment, the metal reflective layer 160 formed on the DBR layer 150 is used to reflect the light of the epitaxial layer back and emit it through the sapphire substrate, and the material of the metal reflective layer 160 directly affects The light extraction efficiency of the flip-chip LED chip; for example, the metal reflective layer 160 can be prepared from a single material; it can also be composed of a reflective layer, a transition layer and a barrier layer formed sequentially by a variety of materials. In specific implementations, The reflective layer can be made of a metal with high reflectivity, such as Al or Ag. When the thickness of the reflective layer is greater than or equal to 1000A, it can have a better reflection effect. The transition layer can be made of Cr, rhodium (Rh), Ti, etc. Formed of metal materials, it is responsible for enhancing the adhesion between the reflective layer and the barrier layer. Because it is located on the reflective layer, it does not hinder the reflection effect of the reflective layer on light. Because the Al, Ag and other metals that make up the reflective layer have Active chemical properties are prone to material migration under the action of temperature and current. Therefore, the barrier layer can be composed of chemically and thermally inactive metal or non-metal oxides. By setting the barrier layer, the reflective layer can be protected in the subsequent It is not easy to be corroded or oxidized during processing, and can hinder the occurrence of electron migration, effectively avoiding chip leakage.

S150, forming a metal conductive layer on the DBR layer and the through hole of the metal reflective layer.

Taking the metal reflective layer formed by the combination of DBR and metal materials commonly used at present as an example, the specific method of this process is: the metal layer formed on the DBR layer not only needs to reflect the light of the epitaxial layer, but also needs to form an ohmic layer. Therefore, the selection of metal materials is greatly restricted; specifically, the metal reflective layer not only needs to have high reflectivity, but also needs to form a good ohmic contact, that is, high conductivity, for example Generally speaking, in the wavelength range of 470-520nm, the best reflectivity of Ag film and Al film is close to 95% and 84% respectively, but the conductivity of Ag and Al is low, it is difficult to form excellent ohmic contact, the prior art The solution provided is to solve this problem by using metals that can form better ohmic contacts, such as Cr, Ti or Ni as the underlying metal, and then plating reflective metal on the underlying metal, such as Cr, Ti or Ni can be used as the underlying metal. The underlying metal, and Al or Ag is used as the reflective layer metal. Although the metal reflective layer formed by this scheme can comprehensively consider the requirements of the two performance indicators of reflectivity and conductivity, the addition of Cr, Ti or Ni will still greatly reduce the Minimize the reflective effect of the metal reflective layer.

In this embodiment, the metal conductive layer 170 is formed on the through holes of the DBR layer 150 and the metal reflective layer 160 to complete the respectively prepared metal conductive layer 170 and the metal reflective layer 160. Therefore, the metal reflective layer 160 and the metal reflective layer 160 are formed. The material forming the metal conductive layer 170 can adopt materials that meet the performance requirements of the respective levels; for example, Ag or Al with higher reflectivity can be used to prepare the reflective layer in the metal reflective layer 160. Finally, Cr or Ti can also be plated to form a transition layer to ensure the adhesion and chemical stability of the metal reflective layer 160, and Au can be further plated to form a shielding layer, through which the reflective layer, the transition layer and the shielding layer simultaneously form a metal Reflective layer 160; in another implementation of this embodiment, after applying a single reflective layer metal, it can be formed by plating oxide or silicide, such as SiO ₂ , TiO ₂ , SiON _x , SiN _x or a combination thereof Barrier layer, since the shielding layer is formed by oxide or silicide, the metal reflective layer 160 in this embodiment may only include the reflective layer and the shielding layer; For example, the metal reflective layer 160 and the metal conductive layer 170 are prepared separately, and the selection of metal materials can meet the needs of reflectivity and conductivity respectively.

Further, S160 in the method provided by this embodiment may include: forming a metal conductive layer 170 filling the through holes of the DBR layer 150 and filling the through holes of the metal reflective layer 160 on the DBR layer 150 and the through holes of the metal reflective layer 160; Optionally, the metal conductive layer 170 forms mutually independent regions at the positions of the through holes; since the through holes formed on the DBR layer 150 and the metal reflective layer 160 overlap, specifically, the exposed part of the N-type semiconductor layer is filled The metal conductive layer 170 of the through hole at position 120 is used to form the ohmic contact of the N-type region, and the metal conductive layer 170 filled with the through hole at the position of the exposed part of the transparent conductive layer 140 is used to form the ohmic contact of the P-type region. The metal conductive layer 170 in the DBR layer 150 and the metal reflective layer 160 can be a metal filling layer whose through hole positions are independent of each other, as shown in FIG. 6 , which is a flip-chip LED chip provided by the embodiment shown in FIG. 1 The chip structure schematic diagram of the process of the preparation method, as shown in Figure 7, is a top view of the metal conductive layer of a flip-chip LED chip provided by the embodiment shown in Figure 1, and Figure 7 only shows the metal conductive layer 170 below metal reflective layer 160, generally, the metal reflective layer 160 can be divided into independent regions located above the N-type semiconductor layer 120 and above the transparent conductive layer 140, the metal reflective layer above the N-type semiconductor layer 120 and the transparent conductive layer 140 160 are separated by isolation holes 163 provided.

In the preparation method of the flip-chip LED chip provided in this embodiment, an epitaxial layer composed of a buffer layer, an intrinsic semiconductor layer, an N-type semiconductor layer, a light-emitting layer, and a P-type semiconductor layer is formed on the substrate. After the P-type semiconductor layer and part of the light-emitting layer are exposed, and part of the N-type semiconductor layer is exposed, a transparent conductive layer, a DBR layer and a metal reflective layer are sequentially formed on the surface of the P-type semiconductor layer, and formed at the same position of the DBR layer and the metal reflective layer. Through holes to expose part of the N-type semiconductor layer and part of the transparent conductive layer, and then form a metal conductive layer on the through hole. In this embodiment, a metal reflective layer for reflecting light and a metal conductive layer for ohmic contact are respectively formed. The flip-chip LED chip prepared by the existing technology solves the problem that the flip-chip LED chip prepared by the prior art, due to the performance limitation of the metal material, cannot meet the requirements of reflectivity and conductivity when preparing the metal reflective layer, which leads to the problem of reduced reflection efficiency. , improving the luminous efficiency of the flip-chip LED chip.

Optionally, in an implementation of this embodiment, S140 may include: directly forming the metal reflective layer 160 on the surface of the DBR layer 150; layer 160 and vias through the DBR layer 150. In this implementation, the through hole for filling the metal conductive layer 170 is formed by photolithography and etching once, which can save the manufacturing process of the flip-chip LED chip and reduce the manufacturing cost.

FIG. 8 is a flowchart of another embodiment of a method for manufacturing a flip-chip LED chip provided by the present invention. In another possible implementation manner of the above embodiment, S140 may include: S141, forming a through hole on the DBR layer; S142, forming a metal reflective layer on the surface of the DBR layer, and forming a metal reflection layer at the position of the through hole of the DBR layer. A through hole on the reflection layer, wherein the coverage of the metal reflection layer does not exceed the coverage of the DBR layer. In this implementation, the through holes on the DBR layer 150 and the through holes on the metal reflective layer 160 are respectively formed through two photolithography and etching processes. Compared with the above-mentioned embodiment, although this method increases the process level, but, Mask patterns made by different photolithography levels, when forming the through hole, the diameter of the through hole on the metal reflective layer 160 can be designed to be greater than or equal to the diameter of the through hole on the DBR layer 150, to ensure the coverage of the metal reflective layer 160 The range does not exceed the coverage of the DBR layer 150, which is beneficial to prevent the leakage of the flip-chip LED chip and improve the use efficiency of the chip.

Further, in this embodiment, the specific manner of forming a through hole on the metal reflective layer 160 at the position of the through hole of the DBR layer 150 in S142 may include: forming a through hole on the metal reflective layer 160, the through hole including the DBR layer The through holes in the layer 150 are at the same position for forming the metal conductive layer 170, and the isolation holes 163 for isolating the metal reflective layer 160 into mutually independent first metal reflective layers 161 and second metal reflective layers 162; Wherein, the through hole on the first metal reflective layer 161 is located on the N-type semiconductor layer 120, and part of the N-type semiconductor layer 120 is exposed, and the through hole on the second metal reflective layer 162 is located on the transparent conductive layer 140, and A part of the transparent conductive layer 140 is exposed. As shown in FIG. 9 , it is a top view of a metal conductive layer of a flip-chip LED chip provided by the embodiment shown in FIG. 8 .

Similarly, in the flip-chip LED chip prepared by the method of this embodiment, the conductive metal layer 170 may also include a first conductive metal layer 171 and a second conductive metal layer 172, specifically, the first conductive metal layer 171 is located on the first On the metal reflective layer 161 , the second metal conductive layer 171 is located on the second metal reflective layer 172 . In a specific implementation, the specific method of forming the metal conductive layer 170 can be: remove part of the metal reflective layer 160, so that the through holes on the first metal reflective layer 161 and the through holes on the second metal reflective layer 162 are respectively connected; The through holes of the layer 150 and the metal reflective layer 160 are respectively formed to connect the first metal conductive layer 171 and the second metal conductive layer 172 , wherein the first metal conductive layer 171 and the second metal conductive layer 172 are independent of each other.

In this embodiment, the first metal conductive layer 171 covers the through hole jointly formed by the DBR layer 150 and the first metal reflective layer 161, and forms an ohmic contact with the first semiconductor layer 120; the second metal conductive layer 172 covers the The through hole formed by the DBR layer 150 and the second metal reflective layer 162 forms an ohmic contact with the transparent conductive layer 140; since the metal conductive layer 170 is located on the metal reflective layer 160, its design structure does not affect the metal reflective layer. 170 reflection effect, therefore, in this embodiment, the first metal conductive layer 171 and the second metal conductive layer 172 are designed as respectively continuous layout structures, which is conducive to the uniform conduction of current in the metal conductive layer 170, and the metal conductive layer 170 The material may be a commonly used electrode material, such as a combination of metals such as Cr, platinum (Pt), Au, Ti, and Al.

It should be noted that, for the structure designed as the mutually independent metal conductive layer 170 at the position of the through hole, or the structure designed as the first metal conductive layer 171 and the second metal conductive layer 172 respectively arranged continuously, the selection conditions are generally It can be: if the barrier layer of the metal reflective layer 160 is made of a metal material, due to its good electrical conductivity, the metal conductive layer 170 can be set as mutually independent regions on the position of the through hole; if the barrier layer is made of an insulating oxide material, it can be designed The first metal conduction layer 171 and the second metal conduction layer 172 are arranged continuously respectively to achieve better conduction effect.

Furthermore, the method provided in this embodiment further includes: S160, forming an insulating layer 180 on the metal reflective layer 160 and the metal conductive layer 170, and forming a through hole exposing part of the metal conductive layer 170 on the insulating layer 180; S170, The metal electrode layer 190 is formed on the through hole of the insulating layer 180 . Specifically, the insulating layer 180 includes at least two through holes, wherein one through hole is located on the first metal conductive layer 171, and the other through hole is located on the second metal conductive layer 172; the metal electrode layer 190 includes covering The first metal electrode layer 191 on the first metal conductive layer 171 and the second metal electrode layer 192 covering the second metal conductive layer 172, the first metal electrode layer 191 is the N pole pin of the flip-chip LED chip , the second metal electrode layer 192 is the P pole pin of the flip-chip LED chip; and the second metal electrode layer 192 are arranged at both ends of the flip-chip LED chip respectively; . In a specific implementation of this embodiment, the insulating layer 180 can be formed by conventional vapor deposition or evaporation, and the insulating layer 180 is etched by a wet method or plasma to expose part of the first metal conductive layer 171 and part of the first metal conductive layer 172; The material of the insulating layer 180 can be, for example, SiO ₂ , SiN, Al ₂ O ₃ , etc. or a combination thereof, and its thickness can generally be between 4000-10000 Å; the metal electrode layer 190 can also be formed by conventional evaporation methods, The material thereof can be, for example, one or a combination of Cr, Al, Ti, Ni, Au, etc., but is not limited to the combination of these metals.

It should be noted that, in the methods for preparing the flip-chip LED chips provided in the above embodiments, after the metal electrode layer is formed, the fabricated wafer can also be ground and cut according to a conventional process to obtain the flip-chip LED chip.

The preparation method of the flip-chip LED chip provided by the embodiment of the present invention adopts basic unit structures such as a transparent conductive layer, a DBR layer, and a metal reflective layer with better performance, and adopts metal conductive layers respectively connected to the N-type area and the P-type area. Layer optimization current distribution not only makes the current spread more reasonable, but also solves the problem that the metal reflective layer acts as a conductive layer in the prior art and needs to add other metals on the bottom, which leads to a decrease in reflectivity, and improves the flip-chip LED to the greatest extent. The product brightness of the chip also prevents the metal reflective layer from participating in the current expansion, avoids the occurrence of metallization electromigration, and improves product reliability.

As shown in FIG. 10 , it is also a structural schematic diagram of an embodiment of a flip-chip LED chip provided by the present invention. The flip-chip LED chip provided in this embodiment is prepared by the method described in any embodiment of the present invention. It should be noted that the flip-chip LED chip provided in this embodiment is prepared by flip-chip mounting method after packaging. Specifically, the metal electrode layer 190, that is, the light-emitting part of the flip-chip LED chip is connected to the bracket, the substrate 100 is upward, that is, above the lighting lamp, and the electrode emits light and passes through the substrate. Flip-chip LED chips were fabricated on sapphire substrates.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (10)

1. A method for preparing a flip-chip LED chip, comprising: growing a buffer layer, an intrinsic semiconductor layer, an N-type semiconductor layer, a light-emitting layer, and a P-type semiconductor layer sequentially on the substrate to form an epitaxial layer; removing part of the P-type semiconductor layer and part of the light-emitting layer to expose part of the N-type semiconductor layer; A transparent conductive layer and a distributed Bragg reflector DBR layer are sequentially formed on the surface of the P-type semiconductor layer, wherein the transparent conductive layer covers the P-type semiconductor layer, and the DBR layer covers the transparent conductive layer and the DBR layer. The N-type semiconductor layer, the light-emitting layer and the P-type semiconductor layer; Forming a metal reflective layer on the surface of the DBR layer, and forming a through hole at the same position of the DBR layer and the metal reflective layer to expose part of the N-type semiconductor layer and part of the transparent conductive layer; A metal conductive layer is formed on the through holes of the DBR layer and the metal reflective layer. 2. The method according to claim 1, wherein the forming a metal reflective layer on the surface of the DBR layer, and forming a through hole at the same position of the DBR layer and the metal reflective layer comprises: directly forming the metal reflective layer on the surface of the DBR layer; Via holes passing through the metal reflective layer and through the DBR layer are simultaneously formed on the DBR layer and the metal reflective layer. 3. The method according to claim 1, wherein the forming a metal reflective layer on the surface of the DBR layer, and forming a through hole at the same position of the DBR layer and the metal reflective layer comprises: forming vias on the DBR layer; Form a metal reflective layer on the surface of the DBR layer, and form a through hole on the metal reflective layer at the position of the through hole of the DBR layer, wherein the coverage of the metal reflective layer does not exceed the DBR layer coverage. 4. The method according to claim 3, wherein the forming the through hole on the metal reflective layer at the through hole position of the DBR layer comprises: A through hole is formed on the metal reflective layer, the through hole includes a through hole for forming the metal conductive layer at the same position as the through hole of the DBR layer, and is used for isolating the metal reflective layer into isolation holes of the first metal reflective layer and the second metal reflective layer which are independent of each other; Wherein, the through hole on the first metal reflective layer is located on the N-type semiconductor layer and exposes part of the N-type semiconductor layer, and the through hole on the second metal reflective layer is located on the transparent conductive layer. and expose part of the transparent conductive layer. 5. The method according to claim 1, wherein the metal reflective layer is formed of a single material; or, The metal reflective layer is composed of a reflective layer, a transition layer and a barrier layer formed sequentially by multiple materials. 6. The method according to claim 1, wherein the forming a metal conductive layer on the through hole of the DBR layer and the metal reflective layer comprises: A metal conductive layer filling the through holes of the DBR layer and the through holes of the metal reflective layer is formed on the through holes of the DBR layer and the metal reflective layer, and the metal conductive layer is formed on the through holes of the through holes. Locations form mutually independent regions. 7. The method according to claim 4, wherein the metal conductive layer comprises a first metal conductive layer and a second metal conductive layer, the first metal conductive layer is located on the first metal reflective layer, and the The second metal conductive layer is located on the second metal reflective layer; then forming the metal conductive layer on the through holes of the DBR layer and the metal reflective layer includes: removing part of the metal reflective layer, so that the through holes on the first metal reflective layer and the through holes on the second metal reflective layer communicate with each other; On the through holes of the DBR layer and the metal reflective layer, respectively connect the first metal conductive layer and the second metal conductive layer, wherein the first metal conductive layer is electrically conductive with the second metal Layers are independent of each other. 8. The method according to any one of claims 1 to 7, further comprising: forming an insulating layer on the metal reflective layer and the metal conductive layer, and forming a through hole exposing part of the metal conductive layer on the insulating layer; A metal electrode layer is formed on the through hole of the insulating layer. 9. The method according to claim 8, wherein the through hole on the insulating layer comprises at least two, wherein one through hole is located on the first metal conductive layer, and the other through hole is located on the first metal conductive layer. The second metal conductive layer is respectively arranged at both ends of the flip-chip LED chip; The metal electrode layer includes a first metal electrode layer covering the first metal conducting layer and a second metal electrode layer covering the second metal conducting layer. 10. A flip-chip LED chip, characterized in that the flip-chip LED chip is manufactured by the method according to any one of claims 1-9.